The collapse of <italic>Mitra</italic>: molecular systematics and morphology of the Mitridae (Gastropoda: Neogastropoda).

Alongside confirmation of the monophyly of the gastropod family Mitridae, a recent molecular phylogenetic analysis disclosed multiple inconsistencies with the existing taxonomic framework. In the present study, we expanded the molecular sampling to 103 species, representing 26% of the 402 extant species currently accepted in the family and 16 of the 19 currently accepted extant genera; 83 species were sequenced for four molecular markers [cytochrome <italic>c</italic> oxidase subunit I (<italic>COI</italic>), 16S and 12S rRNA, and <italic>H3</italic> (Histone 3)]. Molecular analyses were supplemented by morphological studies, focused on characters of the radula and, in a more restricted data set, proboscis anatomy. These data form the basis for a revised classification of the Mitridae. A first dichotomy divides mitrids into two unequal clades, <italic>Charitodoron</italic> and the Mitridae <italic>s.s</italic>. Species of <italic>Charitodoron</italic> show profound differences to all other Mitridae in foregut anatomy (lacking an epiproboscis) and shell morphology (smooth columella, bulbous protoconch of non-planktotrophic type), which leads to the erection of the separate family <bold>Charitodoronidae</bold><bold>fam. nov</bold>. Three traditional subfamilies (Mitrinae, Cylindromitrinae and Imbricariinae) correspond to three of the inferred phylogenetic lineages of Mitridae <italic>s.s.</italic>; we redefine their contents, reinstate Strigatellinae Troschel, 1869 as valid and establish the new subfamily <bold>Isarinae</bold>. In the absence of molecular material, a sixth subfamily, Pleioptygmatinae, is included in Mitridae based on morphological considerations only. To resolve the polyphyly of <italic>Mitra</italic> and <italic>Cancilla</italic> in their current taxonomic extension, we reinstate the genera <italic>Episcomitra</italic> Monterosato, 1917, <italic>Isara</italic> H. & A. Adams, 1853 and <italic>Probata</italic> Sarasúa, 1989 and establish 11 new genera: <italic><bold>Quasimitra</bold></italic>, <italic><bold>Roseomitra</bold></italic>, <italic><bold>Fusidomiporta</bold></italic>, <italic><bold>Profundimitra</bold></italic>, <italic><bold>Cancillopsis</bold></italic>, <italic><bold>Pseudonebularia</bold></italic>, <italic><bold>Gemmulimitra</bold></italic> and <italic><bold>Neotiara</bold></italic> in Mitrinae; <italic><bold>Imbricariopsis</bold></italic> in Imbricariinae; <italic><bold>Carinomitra</bold></italic> and <italic><bold>Condylomitra</bold></italic> are left unassigned to a subfamily. Altogether 32 genera are recognized within the family. Their diversity and distribution are discussed, along with general trends in morphological evolution of the family. [ABSTRACT FROM AUTHOR]